یک حرف تصادفی فارسی

var farsiChar = [1570,1575,1576,1662,1578,1579,1580,1670,1581,1582,1583,1584,1585,1586,1688,1587,1588,1589,1590,1591,1592,1593,1594,1601,1602,1705,1711,1604,1605,1606,1608,1607,1740];
var rand = farsiChar[Math.floor(Math.random() * farsiChar.length)];
var letter = (rand);